Electrical connectors comprise nonconductive housings in which one or more electrically conductive terminals are mounted. The terminals are mechanically and electrically joined to conductive leads, such as wires, cables or conductive areas on a circuit board. Electrical connectors are employed in mateable pairs, wherein the respective housings and terminals in a pair are mateable with one another. Thus, for example, a pair of electrical connectors may enable electrical connections between the conductors of a cable and the printed circuits on a board.
The mateable terminals in a pair of electrical connectors are specifically designed to achieve substantial contact forces against one another in their fully mated condition. These necessary contact forces can result in significant insertion forces during mating, particularly as the number of terminals in a connector increases.
The existence of high insertion forces creates the possibility that the person who mates two electrical connectors will stop short of complete insertion. Incomplete insertion of mated connectors typically will yield less than specified contact forces between the mated terminals and can result in poor electrical performance or unintended separation of the partly mated connectors, particularly in a high vibration environment such as an automobile.
To help ensure complete insertion and to prevent unintended separation of mated connectors, many electrical connector housings are provided with interengageable locks. In particular, one connector may comprise a deflectable latch, while the opposed mateable connector may comprise a locking structure for engagement by the latch. Most connectors with deflectable latches and corresponding lock structures can lockingly retain connectors in their mated condition, but require complex manipulation to achieve mating or unmating. The above described high insertion forces in combination with the manipulation required for the locking means can make mating and unmating particularly difficult.
The prior art includes ramped locking structures which are intended to assist in the complete insertion of the connectors. In particular, the prior art includes connectors where a deflectable latch on one connector and a corresponding locking structure on the mateable connector are constructed such that the resiliency of the latches and the angular alignment of the ramps cooperate to urge the connectors toward a fully mated condition. Examples of connectors with this general construction are shown in U.S. Pat. No. 4,026,624 which issued to Boag on May 31, 1977 and U.S. Pat. No. 4,273,403 which issued to Cairns on Jun. 15, 1981. In these and other similar connectors, the unmating of connectors is rendered difficult by the need to overcome both the contact forces in the terminals and the ramping forces in the latches of the housing. Thus, although these connectors may facilitate the mating of connectors, they require substantially greater forces for unmating.
The manipulation of these connectors is rendered even more difficult by the complex plural deflections that are required within the latch structures both during mating and during unmating. In particular, connectors of this type have required latch structures that gradually deflect about plural axes during mating and unmating, such as a deflection toward or away from the adjacent plane of the connector housing and a deflection parallel to the plane. The excessive forces required for such mating or unmating may be sufficient to damage adjacent parts of the connector, such as the fragile electrical connections between terminals and leads therein.
Improvements over the prior art are disclosed in U.S. Pat. No. 4,900,263 to Manassero et al., dated Feb. 13, 1990 and assigned to the assignee of this invention. That patent provides a positive latch structure for electrical connectors to assist in the final mating thereof and to ensure positively latched engagement in a fully mated condition. Unmating is achieved without the need to overcome ramping forces of deflectable latch components. Generally, deflectable latches undergo only simple deflection about a single axis during mating and a simple deflection about a different axis during unmating, while still achieving positive locking in the fully mated condition. The latches generally are in the form of integrally molded latch arms and are shown in various embodiments. The latch arms are exposed on the outside of the connector housings for ready disengagement. For instance, one embodiment shows latch arms which may be deflected by the use of a disengagement tool such as a screw driver. In another embodiment, the latch arms are joined to the remainder of the associated housing at a fulcrum or root. The latch arms may extend to opposite sides of the root such that portions of the latch arms on one side of the root perform a locking function, while portions of the latch arms on the opposite side of the root may be conveniently activated to permit deflection of the latch arms for disengaging the arms from the opposed connector.
In some instances, it is desirable to have the positive latch means of a connector assembly concealed within a connector housing or housings. In such instances, access to the latch means must somehow be provided, in contrast to the readily accessible latch arms of the embodiments in the 4,900,263 patent. Although the '263 patent discloses valuable improvements over the prior art, the present invention is directed to providing further improvements wherein the latch means can be concealed within the connector assembly and still be made accessible for deflection to disengage the latch means.